Does Healthy Diet Help Prevent COVID-19?

Nadira Noor, Sijing Liu, Yingjian Zhang

Records of Project (DSCI 550)
Sijing, Liu - 12/2021

Food consumption & Malnutrition & COVID-19

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Food categories (as we defined)
Healthy diet

Unhealthy diet

1 General distribution

1.1 Food Consumption Distribution

As the figure shown belown, Vegetables + Vegetal Products (45.5%), which are categorized as healthy food are the most consumed by people worldwidely, followed by Animal fats + Animal Products + Meat (16.3%) and Cereals - Excluding Beer (12.6%).

1.2 Malnutrition Rate

Malnutrition occurs when the body doesn't get enough or balanced nutrients(WHO, 2020).
It covers 2 broad groups of conditions: undernutrition and obesity. The world average malnutrition rate is:

(as shown in intake.describe() - mean row)

1.3 COVID-19 Case Rate

The United States of America has the most confirmed and deaths cases.

To better describe COVID-19 cases rate, we combine the diagnosed cases and the death using concept of Case fatality rate (CFR):

We calculate the CRF of all countries, which are presented below. In the following analysis, we also use CRF besides COVID-19 case rate.

We consider the CRF of Yemen (19.22%) as an outlier and remove it in the following association analysis.

2 Association Detection

2.1 Food consumption & COVID-19 cases

Generally, the relationship between food consumption and countries' confirmed cases and food consumption and deaths cases are very similar.
The top 1 correlations is Animal fats + Animal Products + Meat.

2.2 Food consumption & Malnutrition

Take the average obesity rate as a boundary, we divide the world into HOC (High Obesity Countries) and LOC (Low Obesity Countries).

We start by exploring the most decisive food types: Animal fats + Animal Products + Meat. Research shows they may cause obesity.

HOC have a higher consumption of Animal fats + Animal Products + Meat (belongs to unhealthy diet) and lower consumption of Vegetables + Vegetal Products (belongs to healthy diet).

2.3 Obesity & COVID-19

obesity has a stronger correlation (positive) with COVID-19 Confirmed/ Deaths than undernourished

HOC have more COVID-19 deaths cases

HOC have higher CRF.
The red line represents the average obesity rate among countries. The size of the points corresponds to the country's COVID-19 CRF.

3 Modelling

3.1 Regressor: Food consumption/ obesity → CRF

Train-test split

the result of cross validation looks bad, let's create function to evaluate model on a few different scores (MAE, MSE, R^2)

try to visualize our model's prediction using 'unhealthy diet'

Our Ridge regressor fails to make a good prediction but it somehow captures the tendency of our target.

Imporve by comparing other models (SVG, Random Forest, XGBoost).

XGBoost model shows the best perfromance.
Let's try some hyperparameter tunning with a simple GridSearch:

We can see obesity → CRF performs better than Food consumption → CRF

3.2 Regressor: Food consumption → obesity

4 Observation and Conclusions

Based on all the analysis results above, we can simply generalize the main observations:

Therefore, we can come to our final conclusion that a healthy diet could help prevent COVID-19 only in the way that it gets people rid of obesity. In other words, people who are overweight or obeses due to an imbalanced diet may be at higher risk of illness. The potential reason could be people who eat a well-balanced diet tend to be healthier with stronger immune systems, as suggested by WHO (2021). To avoid getting ill, we suggest obses people eat a healthier diet with more Vegetables + Vegetal Products and less Animal fats + Animal Products + Meat.

This was a difficult year when COVID-19 pandemic made us pay attention to our health. The virus makes it clear that not everything in the world of health is under our control. However, our research proves that many of us are lucky enough to have a say in one important element and that is what we eat. Healthy diets play an important role in our overall health and immune systems (FAO, 2021). The food we put in our bodies directly affects the way that we feel and the way our bodies function. This is as true during an illness as it is before or after.